Swedish researchers followed more than 200 schoolchildren, starting from first through third grade, for nine years. Some children were assigned to an intervention group that received physical education five days a week, plus extra training in motor-physical skills such as balance and coordination. The other children were assigned to a control group that received usual levels of physical education.

The study showed that 96 percent of students in the intervention group achieved grades that made them eligible to advance to upper-secondary school, compared with 89 percent of students in the control group.

This difference was especially evident among boys (96 percent in the intervention group and 83 percent in the control group). The boys in the intervention group had significantly higher grades in Swedish, English, math, physical education and health than those in the control group.

The study also found that in ninth grade, 93 percent of students in the intervention group had good physical motor skills, compared with 53 percent of student in the control group.

"Physical education has been pared down from three lessons a week to one or two," study author Ingegerd, Ericsson of Malmo University, said in a news release. "We scientifically confirm here that daily timetabled physical education and adapted motor skills training not only improves motor skills but also school achievement."